Process and apparatus for treating bituminous sands



Nav. 2, 1.948. R. F. .BAU-ER Erm. 2,453,060-

PROGESS'AND APPARATUS FOR TREATING BITUMINOUS SANDS Filed Aug. s. 1944...36km N5..

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l Patented Nov, 2, i948 PROCESS AND APPARATUS FOR TREATING BITUMINOUSSANDS Robert F. Bauer and Harold J. Matthews, Los AngelesyCalif.,assignors to Union Oil Company of California, Los Angeles, Calif., acorporation` of California Application August 26, 1944, Serial No.551,364

This invention relates to a process and apparatus for separating andtreating bituminous sands and like materia1 into its bituminous andother constituents, one'of the resulting products being composed almostwholly of the bituminous constituents of the material with only a smallamount of other matter and the other product be ing composed of theother matter in which remains only a small quantity of bitumen.

simple and economical process and apparatus capable of operation undercommercial conditionswhich will enable a maximum amount of bitumen to berecovered from the material treated.

Another object is to provide a simple and effective means for causingthe disintegration of the sand and the separation therefrom of thebituminous products.

We have discovered a process by which bituminous products may be readilyand efficiently recovered from bituminous materials in continuousagglomeratlon and flotation steps, wherein a pure bitumen is theresulting product leaving clean mineral matter as a residue. y

The process of our invention may be readily understood by reference tothe attached schematic drawing illustrating one modiilcation of thesame.

Rich bituminous sands are continuously fed into tar sand hopper I, bymeans of a continuous series of trolley cars similar to that designatedas 2. This series of trolley cars operates on a circular narrow gagetrack, such as that designated as 3. The bituminous sands are placed onthe trolley cars by means of trucks, located at the arc opposite tarsand hopper I, and when the trolley cars are full to capacity the rcarsare moved around the circular track motivated by electric motor 4. Whenbituminous sands on the moving trolley cars contact scraper blade 5 thesands are scraped oi and cascaded down into hopper I thus providing ourapparatus with a continuous feeding device. The bituminous materialcascading down through hopper I enters rotary pulper and kminousmaterial during its passage through launder 1 is contacted by a heatingand diluting medium `by the introduction therein of hot water from hotwater heater B vilal lines 9 and I0 and controlled by valve II. Thebituminous material' entering rotary pulper 46 is heated therein bymeans of the aforementioned hot water and disintegrated therein by meansof agitation effected by the rotation of the pulper and blades I2 at'-tached to the walls of the pulper, the combined eilect being to pick upand drop one lump of tar' sand feed upon another and thus bring aboutdisintegration. The pulper is rotated by means of gear I3, which couldbe any suitable driving mech-y anism, which is connected to any suitablemotor, not shown here. The bituminous material during its passagethrough launder 1 and prior to its entrance into the rotary pulper andconditioner B is contacted with a conditioning reagent,y such as sodiumsilicate, sodium carbonate or other reagent as described later. Thisreagentxisin-` troduced, 4preferably as a concentrated :aqueoussolution, into launder 1 from tank 'I4 via line I5 and controlled byvalve I6. `Several changes are effected in the mixture conditioned inrotary pulper 6. Such changes are brought about `by the cumulativeeffect of the numerous variables of time, agitation and/ or abrasion,temperature and concentration of reagent. Regarding the change in thevcharacter of the bituminous material effected in this primaryconditioning several things may be said to occur. Of primary importance,however, is the quite ilne division and dispersion of oil particles. Inthe process of finely dividing the oil` particles, entrained sand isreleased from the oil matrix. If clay is present, as it is to someextent in practically all sands it is thus freed from the oil andsubsequently may be held in the water either ina ilocculated or adispersed form. Whether the clay will be ilocculated or dispersed is afunction of the inherent chemicals in the particular sand and the waterused. In either case however, it is not critical from the standpoint ofthe subsequent flotation step, but may be of importance in the eventthat it is found desirable to recycle the water used in the` subsequentilotation step. In this case, it may be found desirable to add a smallamount of a reagent to effect flocculation of the clays which werepreviously dispersed therein. Such a reagent as sodium chloride might beused. for this purpose or any one of a number of other reagents known tonocculate 'clays might also be employed.

conditioner 6 by means of launder 1, 'I'he bltu- 55 The hotdisintegrated bituminous material and here.

nous sand and. water cascading down throughv nely divided oil particlesmove through pulper 6 as described above and enter screen enclosure i1in stationary housing I9 via channel I9. Screen i1 and channel i9 rotatein conjunction with rotary pulper 6, the screen acting as a siftingdevice whereby the disintegrated bituminous particles and nely dividedoil particles fall through the bottom of the screen and down intolaunder 20.

The large rocks and pebbles, i. e. foreign matter too large to passthrough the screen mesh pass horizontally along the screen and outthrough opening 2i and down through launder 22 to be disposed of in anydesirable manner, not shown rlhe hot mixture of disintegrated bitumilaunder is known as pulp in the bituminous sand industry. The pulp inlaunder 20 is again conditioned/this time with an oil solvent, such askerosene' or other solvent as described below, which is introducedtherein from tank 23,via1ines 24 and 25 controlled by valve 26. Thismixture consisting of hot bituminous pulp, and kerosene in launder 20 isthen introduced into secondary sand conditioner 21, which is providedwith a mixer 29 equipped with impeller blades, and weir 29 formaintaining a liquid level therein. The mixer 28 is rotated by meansofgear 3D which may be any suitable driving mechanism, connected to anysuitable motor, not shown here. The mixture in secondary sandconditioner 27 is conditioned by means of the introduced solvent and theagitation provided by the swiftly revolving shaft and impeller blades,so that the tar and solvent are aerated and tend to separate by notationfrom the sand and water.

AThe addition of the solvent to the above pulp will effect a coagulationor agglomeration of the dispersed oil particles. The solvent will alsodissolve the oil or tar present in the bituminous sands and reduce itsviscosity.and density. The thus conditioned mixture vcomprisingagglomerated oil,

solvent, sand, sodium silicate, and water in the secondary sandconditioner 21 is introduced into primary flotation cell 3| via launder32. The flotation cell may be any one of the recognized notation cellsused in the mining industry, but is preferably one with screw lifts suchas 33, positioned on the bottom of the flotation cell, and operated bymeans of gear 34 which is motivated by any suitable means, not shownhere, so as to operate in such a manner that the sand particles arecarried up the inclined bottom surface to outlet 39 as shown in thedrawing, A water level is maintained in the flotation cell preferablybelow outlety 39, by means of overflow 35 which may also be controlledby valve 36. Hot water is introduced into the flotation cell from hotwater heater 8 via lines 9 and 31 and controlled by valve 38. Theconditioned pulp mixture entering primary flotation cell 3l throughlaunder 32 deposits the solvent and agglomerated oil upon the watersurface therein in the form of a froth and the heavy mineral particlesof sand sink to the bottom of the cell and deposit on rotary screw 33which continuously removes the sand particles up the inclined bottom ofthe cell and cascades it down through launder 39. When the agglomeratedoil-solvent frotnreaches the level of skimmer housing 40, skimmers 4| inskimmer housing 40 are revolved by means of gear 42 which ls motivatedby any suitable means, not shown, through the froth and pick up the topsurfaces and cascade same down through launder 43. The sand releasedfrom the previously prepared pulp, which may still contain a certainpercent of bituminous material. is deposited on screw conveyors 33"andcari-led up the bottom of said flotation cell, as aforementioned,

and is then introduced into tertiary sand conditioner 44, provided withmixer 45, Weir 46, and gear 41 similar to those described in secondarysand conditioner 21. The sand slurry in tertiary sand conditioner 44 isdiluted with Water and solvent if desired, and is again violentlyagitated as in secondary sand conditioner 2l. After this violentagitation the aerated slurry is introduced into secondary notation cell50 via launder 5l, wherein the clean mineral matter is precipitated uponscrew conveyor 52 which is rotated by gear 53 connected to suitablemotivating means not shown, and the bitumen froth floated on the watersurface as described in primary notation cell 3i. Revolving skimmer 54in housing 55 removes the bituminous froth from said water surface andcascades it down the launder `56. The mineral matter or tailings free ofbitumen is removed from secondary flotation cell 50 by means of line 51and deposited on tailings dump. The oil froth in launders t3 and 56 isdiluted by additional solvent, preferably a petroleum fraction,introduced into the launders from tank 23 via lines 24 and 58 andthrough line 59 controlled by valve 6l) and line 6I controlled by valve62, respectively. The diluted bituminousfroths in lines 53 and 56 areblended together and introduced into mixing tank 63` bottom of saidthickener where rake 68 will scrape the fine tailings into line ll whichleads to the tailings pile. The bitumen and petroleum fraction inthickener 56 is removed from the top of the thickener via line l2 andpumped to any suitable site, not shown, wherein the bitumen is separatedfrom the added solvent, for example by distillation. If desired theseparated solvent may be recirculated to tank 23.

In the process as illustrated, hot water is introduced into 'launder 'Iand therein contacting the bituminous sands to act as a diluent and aheating-medium for the purpose of furthering the disintegration of thebituminous sands. The degree of dilution of the bituminous material withhot water in this step plays a very important part in this process.Therefore, when the amount of hot water introduced therein is limited toamounts insufficient to raise said bituminous material to the propertemperature, steam is introduced into said launder by means of line 'I3controlled by valve |4`in order to correct this deciency. Steam may alsobe introduced into rotary pulper 6 by means of line l5.

A proposed modification of the above process is the substitution of ariindependent sand conditioner similar to sand conditioner 21 instead ofusing pulper Bifor the dual purpose of pulping and primary conditioning.

1clean tailings from attacco Conditioning time-Pio' sec. to 30 minutes.

Degree of agitation-fairly violent to very violent. Y

Temperature of pulp-130 F. to 210 F. Goncentration oi reagent-w10 lbs.per ton of tar sands. Tar sand-water ratio-:1 to 1:3 -by weight.

"The optimum operating conditions inf secondary conditioner 2l, i. e.-pulp retention, temperature,

type of agitation, and quantity of solvent used should also bedetermined for each particular tar sand. Ultimately, however, themagnitude of each of the above factors should lie within the followinglimits:

Retention period-10 seconds to 30 minutes. Temperature of conditioning-100v F. to 212 F. Type oi agitationfairly violent to very violent.Quantity of solvent-.0l lbJbbl. of tar to 700 ibs/bbl. A Quality ofsolvent-(see following discussion).

Regarding the characteristics to be desired in the solvent to be used weset forth the following:

i. A low viscosity to minimize the viscosity of the resulting mixtureand thereby facilitate the settling of solids and/ or mineral matterfrom the froth. i

25A lowspeciiic gravity to minimizetthe specie gravity of the resulting.mixture and thereby facilitate the settling of solids and/or mineralmatter from the froth.

3. A high solvent power, or ability to dissolve the tar in a minimumamount f solvent. y l i. A tendency to maintain or improve thehydrophobic condition of the tar, and also to maintain or improve thehydrophillic condition of the sand, so as to make the sand more easilywater.- wettable, and the tar more susceptible to ilotation.

As solvents, petroleum fractions such as cleaners solvent, kerosene andgas oil distillates have been used successfully.

eiiciently than others. Aromatic type hydrocarbons have greater solventpower for most tars than do the non-aromatic hydrocarbons, so for manyoperations benzene, toluene, coal tar fractions. and aromatic extractsfrom petroleum fractions, such as Edeleanu extract from kerosene and thelike,are very useful. Non-hydrocarbons, auch as organic oxygen andsulfur compounds including alcohols, ketones, mercaptans, suldes,thiophenes, and the like are excellent. Basic organic compounds such asthe nitrogen bases, espebe within the following limits: l

ing reagents alkaline compounds such as metal hydroxides ory 6 In thedescription oi thedrawing sodium' silidesignated as the cate and sodiumcarbonate are conditioning reagents, but the invention is not limitedtotheuse of these two. Other conditionwhich may be used are inorganicmetal salts of a lstrong base and a weak acid. Compounds of thealkalimetals. sodium, potassium, lithium and caesiurn, especiallysodium, are greatly preferred. In many instances however, we may alsouse compounds oi other metals such as the alkaline earth metals calcium,barium and strontium and other heavy metals. Ammonium hydroxide may alsobe used. The preferred salts oi these metals are those having polyvalentanions, especially the carbonates and silicates. The phosphates are alsoexcellent, and the pyrophosphates, 'v

phosphitac, sultes, arsenates. suldes, and the like may be employed.

The foregoing description not to be taken as limiting our invention butonly as illustrative thereof since many variations may be made by thoseskilled in the art without depart- .ing from the scope of the followingclaims.

We claim:

l. Apparatus for treating bituminous sands which comprises, incombination: a rotary pulper and sand conditioner provided with meansfor introducing tar sands therein, means for introducing hot water andsteam, means for introducing conditioning agenta'means for pulverizlngand ,agitating the bituminous sands, and means for segregatingconditioned pulp from foreign material; g. secondary sand conditionerprovided with means for introducing pulp therein, means for introducingan oil agglomeration medium, and means for agitating the pulp andagglomerating medium; a flotation cell provided with means forintroducing sand particles and agglomerated oil, means for introducingwater, means for controlling water level, means for removing sandparticles, and means for removing agglomerated oil;

a tertiary sand conditioner provided with means It ls to be noted,however, that certain solvents perform much more means for o removingfor introducing sand particles containing oil, and means for agitatingthe sand and oil particles; a secondary notation cell provided withmeans for introducing the agitated sand and oil particles, the cleansand particles, means for removing the clean oil particles; and meansfor mixing alight petroleum traction with the oil removed from the twoflotation cells; means for mixing the, light petroleum fraction and therecovered oil; and means for removing the light petroleum fraction andrecovered oil from the ne sand tailings.

2. A process for treating bituminous sands t0 separately recover thebitumen and the bitumenfree sand therefrom which comprises introducingbituminous sands, conditioning reagent, hot water and steam. into arotary pulper and sand conditioner having means for agitating andpulverizing said bituminous sands, disintegrating said bituminous sandstherein and thereby forming a pulp comprising disintegrated bituminoussands and water; segregating foreign matter from said pulp and cascadingsaid pulp into a secondary sand conditioner having means for agitatingsaid pulp, introducing into said secondary sand conditioner a solventadapted to dissolve bitumen, agitating and aerating the mixture oi pulpand solvent; cascading the agitated and aerated mixture of pulp andsolvent into a primary dotation cell containing water;

in said primary dotation cell; cascading bituoi our invention isskimming a froth comprising bitumen and solvent from the surface ci thewater 'Ifhe following references are of record in the 15 e of thispatent:

